They know about potholes in Michigan, and the Department of Transportation there says they’re a result of seasonal freeze-thaw cycles. Water seeps through cracks in the pavement and, when it freezes at night, becomes ice that expands, which forces the pavement to rise. Traffic pounds the raised pavement which eventually breaks and creates a hole. Basic physics!

Why do they call them potholes?

One nice bit of folklore relates that the builders of Roman roads in the period before the birth of Christ had to contend with vandals who cut out sections of the pavement to make pots with. The problem with that legend is that Roman roads were made out of stones, lime and coarse sand, not some handy pot material. An American variant has it that the name came from engineers observing rounded pot-shaped natural cutouts in rock formations made by erosion. That one isn’t as cool but is more likely true.

A caller to Car Talk wanted to know what happened to the asphalt from potholes, and it’s explained here. The pavement rises and is knocked down into the resulting hole (like those disappearing Corvettes) by the passing traffic. Gremlins didn’t get it—the asphalt divot is still there.

Which part of the country has the worst roads? Why?

A Washington-based group called TRIP does a regular survey of the worst roads in America, and reports that at least 27 percent of our road surfaces are substandard. Another 27 percent is “mediocre.” Is that better than substandard? The worst experience you’re likely to have in cities with 500,000 or more people, according to TRIP, is in California, which holds down the top four spots—Los Angeles (64 percent poor), San Francisco/Oakland (60), San Jose (56) and San Diego (55). Stands to reason, right, because of how much driving they do out there? There’s not an immediate correlation between bad roads and potholes, and much of California doesn’t get the freeze-thaw cycle that makes the biggest holes, but bad is bad. Also in the Top 20 are very cold places like New York City, Bridgeport (CT), Milwaukee, the greater Boston area (including our fair city, Cambridge) and Hartford.

Can I be made “whole” (get it?) if I hit a pothole?

Good luck. According to the Schlitt Law Firm, you first have to figure out whose road it was, and make sure it’s not covered by pothole exemptions (such as the one New York State passed, giving its roads a liability pass in pothole season, November 15 to May 15). Your claim has to be filed with the appropriate agency, and you know how bureaucracies work—if they can pass the buck, they will. A North Hempstead, Long Island public works employee asks, “How do we know your suspension wasn’t blown in Manhattan?”

Anyway, you’re supposed to take pictures, and document as much as possible that the pothole in question actually caused your damage.

How do they fix potholes?

The temporary method is simply cold asphalt compound slapped in place. The more permanent solution is to use hot-mix asphalt and take greater care reshaping the damaged area. We're guessing, by the horrendous condition of our pavement, that road crews do the former more than the latter.

Who was “Senator Pothole”?

Alphonse D’Amato (R-NY) dubbed himself that in supposed reference to his work as a servant of the people, attentive to their every need—including pothole repair. It didn’t help him keep his seat—the Senator was voted out in 1998. California Governor Arnold Schwarzenegger famously posed with an asphalt rake.

Who's the "pothole Robin Hood"?

A man, Ron Chane, in Jackson, Mississippi who took it upon himself to fix potholes and sign his work "citizen fixed." Did he get a medal? No, he got a police investigation. "Once we saw that people were appreciating what we did, we went out again and made a goal of fixing 100 potholes. We've actually filled 101 potholes, so our mission has been completed," Chane said. Here's some video on it:

You bet, check out the Archbald Pothole State Park in Pennsylvania. The darned thing, formed during the Wisconsin Glacial Period 15,000 years ago, is 38 feet deep in an elliptical shape. It reaches 42 feet in diameter. We love facts like this: it would take 35 fire trucks to fill the pothole, with a volume of 18,600 cubic feet. It would take 140,000 gallons of material from Governor Schwarzenegger’s asphalt rake to fill the pothole.